The immediate effect of mobilisation-with-movement on neuromuscular control of forearm extensors in chronic lateral epicondylalgia: an analysis using mult-channel electromyography

The immediate effect of Mobilisation-with-Movement on neuromuscular control of forearm extensors in chronic lateral epicondylalgia: An analysis using multi-channel electromyography Sharon Tsang1, Johnson Ip1, Mark Yau1, Eric Yip1, Gigi Yuen1, Leanne Bisset2 1 Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong 2 Menzies Health Institute Qld, Griffith University, Gold Coast, Australia BACKGROUND AND AIM: Impaired activation patterns of forearm extensors during gripping have been reported in people with lateral epicondylalgia (LE). Current evidence substantiates the application of Mobilisation-with-Movement (MWM) techniques to improve pain and grip strength, however, its effect on neuromuscular control of forearm extensors remains unknown. This single cohort study examined changes induced by MWM (sustained lateral glide) on pain-free grip strength (PFG) and activation patterns of extensor carpi radialis [ECR], extensor digitorum communis [EDC] and extensor carpi ulnaris [ECU]). METHODS: Forearm extensor activity during a 15% maximal handgrip task was measured using a 64-channel surface electromyography (EMG) in 35 participants with chronic LE. PFG and EMG amplitude during a grip task were compared before and after two conditions, MWM and Sham-MWM, applied to the symptomatic elbow. RESULTS: There was a significant decrease in PFG after Sham-MWM (p=0.006) and a significant decrease in ECU amplitude after MWM (p=0.01). 26/35 participants were identified as positive-responders who exhibited an average of 16.6% increase in PFG post-MWM. Subgroup analysis within the MWM condition showed a significant increase in ECR activity for positive-responders compared to negative-responders (p<0.001). CONCLUSIONS: MWMs applied to the affected elbow resulted in differential changes in forearm extensor activation pattern with a decrease in ECU activity for the whole group and an increase in ECR activity in positive-responder subgroup. Differential responses in neuromuscular control of forearm extensors in people with LE substantiate the importance of subgroup analysis when studying efficacy and mechanisms involved in clinical interventions. KEYWORDS: lateral epicondylalgia, Mobilisation-with-Movement, forearm extensors